The present invention is concerned with electroplated directly plateable plastics for conditions equivalent to and more severe than Service Conditions SC3 and SC4 and more particularly with electroplated directly plateable plastics for such service conditions which have nickel-cobalt alloy strike deposits directly and immediately deposited on the directly plateable plastic surface.
As of now, there have been a number of disclosures with respect to plastic compositions which can be electroplated without the need for the use of complex preplating systems which are necessary when electroplating conventional plastics such as ABS. These disclosures include the Luch U.S. Pat. No. 3,865,699, the Hurley et al. U.S. application Ser. No. 827,986 and PRODUCTS FINISHING, January, 1978, pages 78 to 80. Up to now, the use of such "directly plateable plastics" (DPP) has been hindered by the fact that "precautions" as disclosed in Luch U.S. application Ser. No. 735,312 should be taken in order to insure the stability of the strong initial bond which forms between electrodeposited group VIII metal and the plastic substrate when the plated plastic object is subjected to corrosion and thermal cycling tests appropriate to Service Conditions SC3 and SC4.
The terms "Service Conditions SC3 and SC4" are taken from ANSI/ASTM specification B604-75 second 6.3 Service Condition Number which reads as follows:
6.3 Service Condition Number: PA0 6.31 The service condition number indicates the severity of the service conditions in accordance with the following scales: PA0 6.32 Typical service conditions for which the various service condition numbers are appropriate are given in Annex A1. PA0 6.4 Coatings Appropriate to Each Service Condition Number--Table I shows the coating classification numbers appropriate for each service condition number. PA0 A1.1 Service Condition No. SC 4 (Very severe)--Service conditions that include likely damage from denting, scratching, and abrasive wear in addition to exposure to corrosive environments and temperature extremes; for example, conditions encountered by exterior components of automobiles and by boat fittings in salt water service. PA0 A1.2 Service Condition No. SC 3 (Severe)--Exposure that is likely to include occasional or frequent wetting by rain or dew or strong cleaners and saline solutions and temperature extremes; for example, conditions encountered by porch and lawn furniture, bicycle and perambulator parts, and hospital furniture and fixtures. PA0 A1.3 Service Condition No. SC 2 (Moderate)--Indoor exposure in places where condensation of moisture and temperature extremes may occur; for example, in kitchens and bathrooms. PA0 A1.4 Service Condition No. SC 1 (Mild)--Indoor exposure in normally warm, dry atmospheres with coating subject to minimum wear or abrasion. PA0 5.4 Subject the sample to a thermal cycle procedure as follows: PA0 Each thermal cycle begins with either placing the samples in a room-temperature chamber and heating the chamber up to the high limit or placing the samples directly into a chamber as the high limit. PA0 5.41 Expose the parts for 1 h at the high limit. PA0 5.42 Allow the parts to return to 22.degree..+-.3.degree. C., as quickly as possible and maintain at this temperature for a total cooling period of 1 h. This is frequently accomplished by removing the parts from the chamber, however, some types of apparatus are so constructed that the parts need not be removed during this step. PA0 5.43 Expose the part for 1 h at the lower limit. PA0 5.44 Repeat 5.42. This constitutes one full thermal cycle.
SC 4--very severe service PA1 SC 3--severe service PA1 SC 2--moderate service PA1 SC 1--mild service PA1 NOTE: Suggested definitions of service conditions appear in the Appendix. Alternatively, the definition may be one agreed upon between the purchaser and seller.